In an encapsulation process, a binding agent (such as glass cement) is generally adopted to bind a cover plate and a display substrate. The binding agent is generally formed in an encapsulation region of the display substrate by a printing (such as silk-screen printing) process, then the cover plate is placed on the binding agent so that encapsulation is completed and a display panel comprising the cover plate and the display substrate is obtained.
Because of the drawbacks of the printing technology per se, the binding agent is not flat at an interface of the binding agent and the display substrate. As show in FIG. 1, poor encapsulation is caused, and thus Newton rings and other display defects are likely to occur in the encapsulation region in a display period of the display panel.